The utility model discloses a passive atomic frequency standard with good length and stabilization, particularly the passive atomic frequency standard which is composed of a rf frequency multiplier 1, a microwave multiplier 2, a servosystem 3, a synthesizer 4, a temperature controller 5, a C-field constant current source 6, a physical system 7, a voltage controlled crystal oscillator 8, an isolation amplifier 9 and a travel time counter 14, wherein the servosystem 3 is composed of a frequency selecting amplifier 10 of 79 Hz, a square wave reshaper 11, a first latching drive circuit 12a, a second latching drive circuit 12b, a first latch 13a, a second latch 13b, the travel time counter 14, an SCM 15 and a digital-to-analog converter 16. Because the utility model realizes the purposes of good length and stabilization in one passive atomic frequency standard system, the utility model has the advantages of light weight, small volume and small power consumption. The utility model can be used for passive atomic frequency standard of hydrogen, passive atomic frequency standard of rubidium, and passive caesium-beam atomic frequency standard in the technical fields of navigation positioning, doppler speed measurement, synthetic aperture imaging, dynamic tracking, etc.